Twin Turbo 400 Buildup- '89 Iroc-Z
#203
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
mmhmm, seems like you've spent ALOOOTTTT of time into it. keep up the good work, whens the dyno tune?? what about the first day at the track?
#204
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Time? Oh its been 9 months and it aint fired up yet. Lots of time yes.
Dyno/track? haha soon as i can. Last year the 383 had about 100 miles on it before i hit the track a few times. Then immediately dyno'd it. This motor should be no different really.
Dyno/track? haha soon as i can. Last year the 383 had about 100 miles on it before i hit the track a few times. Then immediately dyno'd it. This motor should be no different really.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
SO Come on did you fire it? Do you have video, OH Crap my keyboard just took a digger (probably from me drooling on it waiting to see the video of this thing running). Hope everything goes well. Awesome build.
Later, Garrett
Later, Garrett
#206
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Fired it up today. Didnt go smoothly but it was running for a few minutes.
Wont run without holding the pedal down abit to keep it going and its idling very rich. Need to tweak my fueling alot but I cant quite figure it all out yet. Ran the battery dead trying to start the car up so many times.
Once i can get it running ok I can set base timing but i just havent been able to get it down yet with this Code 59 and 80 lb injectors.
I can tell you for the few seconds it was running, it sounds amazing! Definately not as quiet as I thought it as gonna be with a 9 to 1 compression motor with turbos in the exhaust path. It sounds sorta like it did before with the 383 just not as lopey.
Wont run without holding the pedal down abit to keep it going and its idling very rich. Need to tweak my fueling alot but I cant quite figure it all out yet. Ran the battery dead trying to start the car up so many times.
Once i can get it running ok I can set base timing but i just havent been able to get it down yet with this Code 59 and 80 lb injectors.
I can tell you for the few seconds it was running, it sounds amazing! Definately not as quiet as I thought it as gonna be with a 9 to 1 compression motor with turbos in the exhaust path. It sounds sorta like it did before with the 383 just not as lopey.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
so how is it going....
#209
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
just trying to get it running right. having issues with code $59 that seem to be more electrical wiring related than actual code stuff. Still havent driven the car except for in the driveway. sounds good, just needs tuned and i'm having difficulty. Honestly didnt expect it to be so difficult. I'm new to the whole map sensor stuff and especially this code 59. Just learning whats all what in this code
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
i dont even know what code 59 is but i found this on google, hope this helps www.code59.org
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
any updates orr? its lookng good cant wait to see some vid
#216
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Yeah i tried the new ecm but that didnt work, so i checked for loose wiring and found a bad connection to my alternator and the batter drained abit and would not restart the car. My injector offset tables vs voltage need tweaked some.
Now i have been looking for the cause of some sort of ticking like sound... but its not a tick like metal, sounded more like an exhaust leak. I thought maybe a rocker arm but as i started taking the downpipe off, i started the car and the sound was amplified so I know its definately a leak. I found a small pin hole in the weld on the wastegate to downpipe tube and its leaking a touch. I think thats the only thing thats leaking and i hope its not a rocker arm as well. Its not very loud but you can hear it.
I may try to quick patch that hole with a tack weld and see what happens.
I still have heat issue from front to rear of the motor. Front cylinders are definately abit leaner looking (plugs) than rears and the rears are running much hotter. But the mid cylinders 5/6 are also very hot. I may need more timing at idle and maybe more fuel or so. Its alrady at mid 14's to 1 idle air fuel ratio
Now i have been looking for the cause of some sort of ticking like sound... but its not a tick like metal, sounded more like an exhaust leak. I thought maybe a rocker arm but as i started taking the downpipe off, i started the car and the sound was amplified so I know its definately a leak. I found a small pin hole in the weld on the wastegate to downpipe tube and its leaking a touch. I think thats the only thing thats leaking and i hope its not a rocker arm as well. Its not very loud but you can hear it.
I may try to quick patch that hole with a tack weld and see what happens.
I still have heat issue from front to rear of the motor. Front cylinders are definately abit leaner looking (plugs) than rears and the rears are running much hotter. But the mid cylinders 5/6 are also very hot. I may need more timing at idle and maybe more fuel or so. Its alrady at mid 14's to 1 idle air fuel ratio
#218
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Drove the car alot yesterday...its on the road and running pretty good. Havent romped on it yet as it starts to go lean above 3500 rpm but between there and idle, its a monster. These turbos are gonna spool stupid quick! I should have gone bigger on the housing i think. They already start spinning up at 2500 rpm or so and are about to start making boost at 3000 ish from what i can tell and thats at 3/4 throttle roll in's
It sounds absolutely sick and that Tial BOV is reallly loud
It sounds absolutely sick and that Tial BOV is reallly loud
#219
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Drove the car alot yesterday...its on the road and running pretty good. Havent romped on it yet as it starts to go lean above 3500 rpm but between there and idle, its a monster. These turbos are gonna spool stupid quick! I should have gone bigger on the housing i think. They already start spinning up at 2500 rpm or so and are about to start making boost at 3000 ish from what i can tell and thats at 3/4 throttle roll in's
It sounds absolutely sick and that Tial BOV is reallly loud
It sounds absolutely sick and that Tial BOV is reallly loud
Awesome! Make sure to get vids!
#220
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Nice dude.... Good to see another good looking 3d Gen Turbo setup.
If you need help with Code 59 let me know. I work with it on Sy/Ty's alot.
Also Know Dig and Jeff and a few others that are better than me as well.
Jeff has a twin turbo Typhoon SBC. There's some stuff you gota know to set the
perameters so it won't cut fuel with 2 extra pulses it sees that it's not use to.
Found that on Jeff's.
~SCott
UR50SLO@aol.com
If you need help with Code 59 let me know. I work with it on Sy/Ty's alot.
Also Know Dig and Jeff and a few others that are better than me as well.
Jeff has a twin turbo Typhoon SBC. There's some stuff you gota know to set the
perameters so it won't cut fuel with 2 extra pulses it sees that it's not use to.
Found that on Jeff's.
~SCott
UR50SLO@aol.com
#221
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Please share the information I've been getting help from a few other guys here that know code 59. So far so good.
I wasnt able to take the car over 3800 rpm because of what i thought was a lean spot which it probably is, but its acting like a rev limiter so i was wondering if i had fuel cutoff or something.
Other than that i got the car running ok on the 80lb injectors. idles fine and adjusted the voltage tables to deal with battery voltage drops. Car will idle ok even at 10 volts to the system..just goes very lean but it works
I wasnt able to take the car over 3800 rpm because of what i thought was a lean spot which it probably is, but its acting like a rev limiter so i was wondering if i had fuel cutoff or something.
Other than that i got the car running ok on the 80lb injectors. idles fine and adjusted the voltage tables to deal with battery voltage drops. Car will idle ok even at 10 volts to the system..just goes very lean but it works
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Man Orr can't wait to see what that thing puts down.
#223
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
See where your fuel cut/rev limit is set in Tuner Pro.
Jeff's Twin Turbo Ty was doing the exact same thing.
Keep in mind that your Rev limit being set at 6500 will come in much earlier since the V8 has two more pulses or rev counts than a 4.3L.
Put the rev limit up high and see if it go's away.
What's your wide band saying?
~Scott
Jeff's Twin Turbo Ty was doing the exact same thing.
Keep in mind that your Rev limit being set at 6500 will come in much earlier since the V8 has two more pulses or rev counts than a 4.3L.
Put the rev limit up high and see if it go's away.
What's your wide band saying?
~Scott
#224
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
i have my fuel cut set to 6687 for 8 cylinder. There are 3 tables for 8 6 and 4 cyl. Should i set it to infinite and just use my mallory 685 to control rev limiter? I thought the 3 tables would take into account the differences in pulses?
Havent checked my logs yet, will do so later tonight. But i did hit 2.7 lbs of boost at some point two nights ago and i never got on the gas 100%, no more than 75% i'd say Wastegates have 6-7 lb spring in them and BOV spring needs shimmed abit more, as i got the lightest Tial spring and my motor makes more vacuum than its rated at
Havent checked my logs yet, will do so later tonight. But i did hit 2.7 lbs of boost at some point two nights ago and i never got on the gas 100%, no more than 75% i'd say Wastegates have 6-7 lb spring in them and BOV spring needs shimmed abit more, as i got the lightest Tial spring and my motor makes more vacuum than its rated at
#225
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
I think Jeff had his set for 8cyl too.
He chased his tail for some time till we were in the Sy/Ty Chat room all talking and I asked where his rev limit was set... and I said it's getting 2 more pulses than normal seeing as the ECM your using/he is using was originally setup for a 4.3L.
It'll drive 8 injectors no problem...
You have differnt drivers in the ECM for the bigger injectors correct..?
Try the Sy/Ty Chat too (go to syty.net then chat is at top blinking) make user name
Jeff can help too.. he's always in there and so am I during the day.
Be glad to help you out.
He chased his tail for some time till we were in the Sy/Ty Chat room all talking and I asked where his rev limit was set... and I said it's getting 2 more pulses than normal seeing as the ECM your using/he is using was originally setup for a 4.3L.
It'll drive 8 injectors no problem...
You have differnt drivers in the ECM for the bigger injectors correct..?
Try the Sy/Ty Chat too (go to syty.net then chat is at top blinking) make user name
Jeff can help too.. he's always in there and so am I during the day.
Be glad to help you out.
#226
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Well the setup i'm running now is just 730 ecm found in 91-92 TPI cars that runs high-Z injectors and I got Dig's 60 lb bin from code59.org and scaled it 75% to work with 80 lb injectors like i have. It worked ok but i had alot of tweaking to do and now have it somewhat ok. Coldstart needs worked and i may richen up idle abit but other than that its running well.
I'm using siemens 80lb high-z injectors and they are doing good. I really needed to adjust the voltage offset table to get idle from being so damn jumpy but its running now even with battery voltage as low as 10 volts (alternator wire popped off while running and battery drained) So i know its working well.
Jeff i believe had 84lb low Z injectors. I tried the bin he had on code59.org and it didnt work well for me. I guess there may be a difference in low z and high z stuff but all motors are different. My 383 tune didnt work on several other similar combos
I may have to check out those sites now that I have gotten this far
I'm using siemens 80lb high-z injectors and they are doing good. I really needed to adjust the voltage offset table to get idle from being so damn jumpy but its running now even with battery voltage as low as 10 volts (alternator wire popped off while running and battery drained) So i know its working well.
Jeff i believe had 84lb low Z injectors. I tried the bin he had on code59.org and it didnt work well for me. I guess there may be a difference in low z and high z stuff but all motors are different. My 383 tune didnt work on several other similar combos
I may have to check out those sites now that I have gotten this far
#227
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
At least you have a startup file. Or a place to start.
I thought you were using a Sy/Ty ECm... as it's all setup for boost and everything.
Might be somthing to consider. Your wideband is tied into the ECM correct...?
Do you have a digital readout/gauge inside?
Running one wideband or two? Hop over to Sy/Ty chat real quick.. I'll go get in there.
~Scott
I thought you were using a Sy/Ty ECm... as it's all setup for boost and everything.
Might be somthing to consider. Your wideband is tied into the ECM correct...?
Do you have a digital readout/gauge inside?
Running one wideband or two? Hop over to Sy/Ty chat real quick.. I'll go get in there.
~Scott
#228
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
I have to register. I made my same screen name but need to wait for administrator to approve i guess.
Yeah i'm not running the truck ECM but I repinned my original harness to run the code and so far it works fine.
I have LC-1 wideband wired into ECM and its reading the same as my guage in the car. I am planning ongetting another LC-1 for the other downpipe. I have bungs in both.
Yeah i'm not running the truck ECM but I repinned my original harness to run the code and so far it works fine.
I have LC-1 wideband wired into ECM and its reading the same as my guage in the car. I am planning ongetting another LC-1 for the other downpipe. I have bungs in both.
#229
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
I think if you get on the board... up at the top it should say "Chat" in the middle with blinking lights.
HEre's another way to get to chat.
http://chat.sytysogt.com/flashchat.php
HEre's another way to get to chat.
http://chat.sytysogt.com/flashchat.php
#231
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
You have to register for chat too.. make a user name and password.
Enter it through the main page on syty.net where it says chat and then it'll let you set your user name/password.
Enter it through the main page on syty.net where it says chat and then it'll let you set your user name/password.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
wow great documented build thread, wheres the pictures of the hood and the videos lol
#233
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Originally Posted by Orr89RocZ
Jeff i believe had 84lb low Z injectors. I tried the bin he had on code59.org and it didnt work well for me. I guess there may be a difference in low z and high z stuff....
#234
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Very nice work! Please don't fall into the bigger is better trap on turbine size, especially for a street car. Leave that for the slow ricers. Your smaller a/r choice is much better here. You could easily run well into the low 9's on a street car with the exh housings you have. Going bigger will just make it harder to get into power. Go even further and the car has such trouble making boost it actually slows down.
Backpressure (and then expansion through the diffuser) is what powers the turbines. The turbines run like compressors in reverse basically. Having backpressure doesn't stop you from making tremendous power at all. It does make the hot side piping hard to seal on a turbo car though.
Pump gas will not support alot of boosted power. Esp with 9:1 CR. I'd say anything more than about 12 psi will be pushing it then. And that assuming it is all properly tuned, at every significant speed/load point.
And please be sure to retard the timing significantly as boost increases. This is critical to success here.
Thank you for so generously sharing your build up!
TurboTR
Backpressure (and then expansion through the diffuser) is what powers the turbines. The turbines run like compressors in reverse basically. Having backpressure doesn't stop you from making tremendous power at all. It does make the hot side piping hard to seal on a turbo car though.
Pump gas will not support alot of boosted power. Esp with 9:1 CR. I'd say anything more than about 12 psi will be pushing it then. And that assuming it is all properly tuned, at every significant speed/load point.
And please be sure to retard the timing significantly as boost increases. This is critical to success here.
Thank you for so generously sharing your build up!
TurboTR
Last edited by TurboTR; 10-06-2009 at 03:23 PM.
#235
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
For reference, here's one of my friend's past twin turbo race cars.
It was a door slammer GS, relatively heavy at over 3200 lbs. Powered by a 274" v6 with a powerglide. It went a best of 7.9x @ 185 (no nitrous), being rather conservative on the tune (1st gen FAST system).
Real world point I'm trying to make is, note the size of those monster turbines on the engine (NOT)... These smaller hsgs were a sound engineering choice for this car, even into the 7's. Again, no nitrous.
Hope that helps.
TurboTR
It was a door slammer GS, relatively heavy at over 3200 lbs. Powered by a 274" v6 with a powerglide. It went a best of 7.9x @ 185 (no nitrous), being rather conservative on the tune (1st gen FAST system).
Real world point I'm trying to make is, note the size of those monster turbines on the engine (NOT)... These smaller hsgs were a sound engineering choice for this car, even into the 7's. Again, no nitrous.
Hope that helps.
TurboTR
#236
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Pump gas will not support alot of boosted power. Esp with 9:1 CR. I'd say anything more than about 12 psi will be pushing it then. And that assuming it is all properly tuned, at every significant speed/load point
#238
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Well for now i'm be running just 6-7 lbs and then looking to get boost controller to hit 15. Meth may wait but if you dont think it will do without, then maybe i will get it sooner. Or just mix race gas in the tank.
If I did my turbo math right, this thing should still go high 10's on 7psi
If I did my turbo math right, this thing should still go high 10's on 7psi
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Well in my experience, 15 psi would be pushing it on 9:1 and pump gas. But yes, there are people who push these things. And the internet is vast these days, such that ~ everyone has a cousin who knows someone who ran 7's on pump gas and 40 psi boost with a Honduh 4 cyl. We almost never hear about the big mess it left 2 weeks later though. Personally I prefer to err on the side of conservative, as opposed to needing a push broom to sweep up after the car. But of course it's your (very nice) project, not mine, so JMO and YMMV
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Originally Posted by Orr89RocZ
There are guys pushing that much on much higher compression than what i have..i figured i could easily get 15psi on this setup probly tuned with pump gas and maybe some meth injection for safety....
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Yeah I've known Lawrence since the early 90's too And for awhile he also was pushing a high timing approach for back then too, until I think the stack of blocks with custom ventilation in them became too big to fit in the dumpster out back. His motto was "if you're not breaking parts, you're not going fast enough", end quote. Personally I live by a somewhat differerent motto. Some people are more tolerant of knock, blown headgaskets, broken parts, etc than others it seems.
Just trying to impart some helpful, cautious advice based on years of actual experience. I have real time cylinder pressure monitoring gear of my own (and used it professionally for several years). You can learn alot from that gear, as you might expect. Don't want to step on any 3rd gen toes here. We'll just have to respectfully agree to disagree. Peace, out.
TurboTR
Just trying to impart some helpful, cautious advice based on years of actual experience. I have real time cylinder pressure monitoring gear of my own (and used it professionally for several years). You can learn alot from that gear, as you might expect. Don't want to step on any 3rd gen toes here. We'll just have to respectfully agree to disagree. Peace, out.
TurboTR
#243
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Hey no harm, its all good advice. I honestly think I wont need much more than 8-10psi to have some serious fun in this car. 15+ on race gas tune is for the track but my car is only legal to 10.0's so i cant get to crazy with it
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Totally. With your cubes it should be alot of fun with even "just" 10 psi.
With race gas and more boost, it should run, umm quite well
TurboTR
With race gas and more boost, it should run, umm quite well
TurboTR
#245
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Unfortunately though, blown head gaskets, rods and pistons are very common in the turbo buick world. A lot of the guys that are still running the Bob Bailey modified ECM's, and turbo tweak chips, in conjunction with their scanmaster's, etc, have to worry about those issues. Nowadays, with 16 and 32-bit processors, detonation is much easier kept in check, and the only real issue then is the credibility of the engine builder himself. Those who know how to tune for boost, 99.9% of the time, their engines will blow because of a flaw in the engine's assembly. But yeah, 15-psi is more than enough for a 400-SBC, as at that level, the cubic inch displacement is doubled....
Originally Posted by TurboTR
Yeah I've known Lawrence since the early 90's too And for awhile he also was pushing a high timing approach for back then too, until I think the stack of blocks with custom ventilation in them became too big to fit in the dumpster out back. His motto was "if you're not breaking parts, you're not going fast enough", end quote. Personally I live by a somewhat differerent motto. Some people are more tolerant of knock, blown headgaskets, broken parts, etc than others it seems.
Just trying to impart some helpful, cautious advice based on years of actual experience. I have real time cylinder pressure monitoring gear of my own (and used it professionally for several years). You can learn alot from that gear, as you might expect. Don't want to step on any 3rd gen toes here. We'll just have to respectfully agree to disagree. Peace, out.
TurboTR
Just trying to impart some helpful, cautious advice based on years of actual experience. I have real time cylinder pressure monitoring gear of my own (and used it professionally for several years). You can learn alot from that gear, as you might expect. Don't want to step on any 3rd gen toes here. We'll just have to respectfully agree to disagree. Peace, out.
TurboTR
#246
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
u guys wouldnt happen to have any used T3s laying around would ya? lol. looks good Orr89rocZ!! keep it up
just rode in my friends 92 stang with a vortec supercharger... dynoed at 411rwhp (mild 302 with holley top end package) it wasnt as fast as i thought it would be. belt was slipping and only made 10psi max at one point. id be happy with twin T3s out back of the car with 6-8psi on my 383
post some pics and vids soon! i had a tick too upfront when i just started my 383, i thought it was the rockers so i pulled the valve cover and found that 2 were alil loose even with the poly locks. didnt really change anything tho, guess its just loud. dunno how being hydraulic roller cam and full roller proform rockers
just rode in my friends 92 stang with a vortec supercharger... dynoed at 411rwhp (mild 302 with holley top end package) it wasnt as fast as i thought it would be. belt was slipping and only made 10psi max at one point. id be happy with twin T3s out back of the car with 6-8psi on my 383
post some pics and vids soon! i had a tick too upfront when i just started my 383, i thought it was the rockers so i pulled the valve cover and found that 2 were alil loose even with the poly locks. didnt really change anything tho, guess its just loud. dunno how being hydraulic roller cam and full roller proform rockers
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Car: Turbo power
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Unfortunately, centrifigually supercharged street cars are generally not as fast as their peak dyno hp numbers might suggest. The main problem is, they fall way off boost on each upshft. It's sort of analogous to having too large a turbine a/r, as we mentioned above.
Been working with a supercharged Camaro lately (BBC + Procharger F3R + FAST XFI) that makes around 2,500 hp or so at peak boost of about 30 psi. It has a powerglide though (lol), and on the 1-2 upshift the boost drops some ~ 8 psi, then slowly climbs back upwards as the rpm climbs again. For sure the car is quite fast already (6 sec car at well over 200 mph), don't misunderstand, but it would also pick up significantly without the big boost (power) drop on the upshift. The Achilles heel of a centrifigual blower. The boost curve is basically = to the rpm curve. So during an actual run it spends most of it's time well down from peak boost and peak hp. If it had turbos, that would be a much different story. But OTOH, the centrifugual is a relative joy to stage and launch, compared to a big turbo.
TurboTR
Edit- here's a pic of the setup:
Been working with a supercharged Camaro lately (BBC + Procharger F3R + FAST XFI) that makes around 2,500 hp or so at peak boost of about 30 psi. It has a powerglide though (lol), and on the 1-2 upshift the boost drops some ~ 8 psi, then slowly climbs back upwards as the rpm climbs again. For sure the car is quite fast already (6 sec car at well over 200 mph), don't misunderstand, but it would also pick up significantly without the big boost (power) drop on the upshift. The Achilles heel of a centrifigual blower. The boost curve is basically = to the rpm curve. So during an actual run it spends most of it's time well down from peak boost and peak hp. If it had turbos, that would be a much different story. But OTOH, the centrifugual is a relative joy to stage and launch, compared to a big turbo.
TurboTR
Edit- here's a pic of the setup:
Last edited by TurboTR; 10-07-2009 at 12:23 PM.
#248
Supreme Member
iTrader: (15)
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
arent other fall backs of superchargers that they can only make as much max boost as high as you rev... example being that turbos can make more boost bc supercharger max boost is directly rated to max RPM. except for the option of smaller pullies. a good thing about superchargers tho is less weight (turbo has lots of plumbing), less heat (doesnt always need an intercooler depending on boost etc) but they make less power and take power from the engine to operate.
is there any issues with running a MAF with a turbo or dual turbos? seems that most ppl switch to the 730 ecm and speed density
is there any issues with running a MAF with a turbo or dual turbos? seems that most ppl switch to the 730 ecm and speed density
#249
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
MAF cant handle a healthy n/a 383 without needing PE mode to add extra fuel. Boost would only make it worse. If you run low power setup, and know exactly when boost comes in rpm wise, you can use PE mode on a MAF car to add fuel for boost. Its a band aid tho much like a fuel management unit (FMU) that is used to increase fuel pressure with boost to add fuel. Its not a preferred setup tho. MAP sensor is needed for proper fuel addition with boosted applications.